Hi, I'm not sure, but I think they might be rouens. If your not familiar with this kind, they look like a mallard only twice as large, and they can't fly. I've had them in the past. They're pretty cool.

The little striped ducklings head is about as big around as a dime, and it is very very tiny. It is the size of the smallest bantam chick I have. The other one is a bit bigger, and is black with a few yellow "hairs" on its chest. Don't know if that helps any.

I am guessing that the striped one is a Rouen, and the other is a cayuga. Not completely sure though, just going off of pictures in a catalogue, lol.